魔术方法

<?php

declare(strict_types=1);

final class OrderActions
{
    public function __call(string $name, array $arguments): string
    {
        if (!in_array($name, ['cancel', 'resendReceipt'], true)) {
            throw new BadMethodCallException("Unsupported action: {$name}");
        }
        if (count($arguments) !== 1 || !is_int($arguments[0])) {
            throw new InvalidArgumentException('Expected one integer order ID');
        }

        return match ($name) {
            'cancel' => $this->cancelOrder($arguments[0]),
            'resendReceipt' => $this->resend($arguments[0]),
        };
    }

    private function cancelOrder(int $orderId): string
    {
        return "Order {$orderId} cancelled";
    }

    private function resend(int $orderId): string
    {
        return "Receipt {$orderId} resent";
    }
}

$actions = new OrderActions();
echo $actions->cancel(17), "\n";
echo $actions->resendReceipt(23), "\n";

try {
    echo $actions->delete(31);
} catch (BadMethodCallException $error) {
    echo $error->getMessage(), "\n";
}

<?php

declare(strict_types=1);

final class PercentageDiscount implements Stringable
{
    public function __construct(private int $basisPoints)
    {
        if ($basisPoints < 0 || $basisPoints > 10_000) {
            throw new InvalidArgumentException('Invalid discount');
        }
    }

    public function __invoke(int $priceInCents): int
    {
        return intdiv($priceInCents * (10_000 - $this->basisPoints), 10_000);
    }

    public function __toString(): string
    {
        return number_format($this->basisPoints / 100, 2) . '% off';
    }
}

$discount = new PercentageDiscount(1_500);
echo $discount, "\n";
echo 'callable: ', is_callable($discount) ? 'yes' : 'no', "\n";
printf("final price: $%.2f\n", $discount(12_000) / 100);

<?php

declare(strict_types=1);

final class Address
{
    public function __construct(public string $city) {}
}

final class CartDraft
{
    public function __construct(
        public Address $address,
        private array $items,
        private string $sessionToken,
    ) {}

    public function __clone(): void
    {
        $this->address = clone $this->address;
        $this->sessionToken = '';
    }

    public function __serialize(): array
    {
        return ['address' => $this->address, 'items' => $this->items];
    }

    public function __unserialize(array $data): void
    {
        if (!($data['address'] ?? null) instanceof Address || !is_array($data['items'] ?? null)) {
            throw new UnexpectedValueException('Invalid cart data');
        }
        $this->address = $data['address'];
        $this->items = $data['items'];
        $this->sessionToken = '';
    }

    public function hasSessionToken(): bool
    {
        return $this->sessionToken !== '';
    }
}

$original = new CartDraft(new Address('Paris'), ['BK-1' => 2], 'secret');
$copy = clone $original;
$copy->address->city = 'Lyon';
$restored = unserialize(serialize($original), [
    'allowed_classes' => [CartDraft::class, Address::class],
]);

echo "original: {$original->address->city}\n";
echo "copy: {$copy->address->city}\n";
echo 'clone token: ', $copy->hasSessionToken() ? 'yes' : 'no', "\n";
echo "restored: {$restored->address->city}\n";
echo 'restored token: ', $restored->hasSessionToken() ? 'yes' : 'no', "\n";